Integrated IP network

ABSTRACT

To provide an integrated IP network containing therein a plurality of separated IP networks with a variety of characteristics, such as IP telephone network, IP video network, IP electronic text network, best effort network, IP data multicast network and IP-based TV broadcast network. In the integrated IP network there are virtually installed a plurality of IP networks with various features, such as IP telephone network, IP video network, IP electronic text network, best effort network, IP data multicast network and IP-based TV broadcast network. An address management table is set in each of the network node devices installed at input points through which the integrated IP network is accessed from outside. The address management table is registered beforehand with terminal addresses and port numbers identifying the application programs (AP) in the terminal. The address and port number written in the IP packet entered into the integrated IP network are compared with those registered in the address management table to route, inside the integrated IP network, the IP packet to an appropriate IP network. The port number may not be used and only the addresses may be compared.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.09/568,515, filed on May 9, 2000, now U.S Pat. No. 6,711,623 whichclaims priority to Japanese Application No. 128956/1999, filed on May10, 1999, and Japanese Application No. 13154/2000, filed on Jan. 21,2000, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an integrated IP (Internet Protocol)network of an IP network for computer communication based on the TCP/IP(Transmission Control Protocol/Internet Protocol) technology.

2. Description of the Related Art

The IP network designed to send and receive digitized voice dataaccording to the TCP/IP technology (hereinafter referred to as an “IPtelephone network”) uses a communication circuit speed of about 64 Kbpsto keep the arrival time of voice data below, for example, 0.1 second.An IP telephone network to send and receive a compressed video image ofTV according to the TCP/IP technology (hereinafter referred to as an “IPvideo network”) uses a communication circuit speed of, for example, 1.5Mbps and allows a video data arrival time of a few minutes.

The IP telephone network to transfer texts of electronic vouchersaccording to the TCP/IP technology (hereinafter referred to as an “IPelectronic text network”) has a communication circuit speed of about 128Kbps to keep the data arrival time less than 1 second. In this case,because the reliability is given a greater importance than those ofvoice transmission and TV video transmission, the communication erroroccurrence rate is kept less than one one-hundredth those of the IPtelephone network and IP video network.

Other IP telephone networks include, for example, an “IP data multicastnetwork” that transfers IP data such as electronic books and electronicnewspapers from one sending source to a plurality of destinations, andan “IP-based TV broadcast network,” an IP audio-visual network, whichtransfers (or broadcasts) both TV's voice data and video data to aplurality of destinations using multicast technology, one oftechnologies. These multicast type network differ from the preceding IPtelephone networks in that they do not employ the one-to-onecommunication scheme.

As shown in FIG. 1, in the conventional IP network 20 as represented bythe Internet, an IP packet 26-1, including IP telephone data, IP videodata and IP electronic voucher text data, is dispatched from a terminal23-1 within a LAN 21 to a terminal 23-2 in a LAN 22 through a router24-1 in the LAN 21 and routers 22-1 to 22-4 in the IP network 20 andthrough a router 24-2 in a LAN 22. The Internet, while it cannotguarantee the communication speed and others during the IP transfer, isgenerally called a “best effort network” in the sense that it makes thebest effort. The IP telephone data, the IP video data and the IPelectronic voucher text data flow in an intermingled manner through thecommunication circuits in the IP network 20, as in this example. Thatis, the conventional IP networks do not contain therein a plurality ofseparated IP networks with various characteristics, such as the IPtelephone network and IP video network, the IP electronic text network,the best effort network, the IP data multicast network and the IP-basedTV broadcast network. For this reason and others, the IP telephonenetwork, IP video network, IP electronic text network, best effortnetwork, IP data multicast network and IP-based TV broadcast networkhave been constructed separately, giving rise to a problem of anincreased overall cost of the entire IP network.

By referring to FIG. 2 a multicast type IP network 27-1 that transfersdata from one originating source to multiple destinations will beexplained. Reference numbers 27-2 to 27-9 represent routers, of which27-2, 27-6, 27-7, 27-8 and 27-9 in particular are routers to which theusers' IP terminals 28-1 to 28-9 can connect via communication circuitsand which are also called network nodes. The routers 27-3, 27-4, 27-6,27-7, 27-8 have a multicast-by-router table that tells each router tosend a received IP packet to a plurality of communication circuitsaccording to a multicast address contained in the received IP packet. Inthis embodiment, the multicast address specifies “MA1”. The IP terminal28-1 sends an IP packet 29-1 which has a multicast address “MA1” throughthe router 27-2. When it reaches the router 27-3, the router 27-3 copiesthe IP packet 29-2, checks the multicast-by-router table and transfersIP packet 29-3 and IP packet 29-4 onto communication circuits. Therouter 27-4 copies the received IP packet 29-3 and, according to themulticast-by-router table, transfers IP packet 29-5 and IP packet 29-6onto communication circuits. The router 27-5 has no multicast-by-routertable and so the IP packet 29-4 passes through the router 27-5 to betransferred as IP packet 29-7 to the router 27-8. The router 27-6 copiesthe received IP packet 29-5, checks the multicast-by-router table andtransfers IP packet 29-8 to IP terminal 28-2 and IP packet 29-9 to IPterminal 28-3. The router 27-7 copies the received IP packet 29-6,references the multicast-by-router table and transfers IP packet 29-10to IP terminal 28-4 and IP packet 29-11 to IP terminal 28-5. The router27-8 copies the received IP packet 29-7, references themulticast-by-router table and sends the IP packet 29-12 to IP terminal28-6, IP packet 29-13 to IP terminal 28-7 and IP packet 29-14 to IPterminal 28-8. When the source terminal 28-1 sends electronic books andelectronic newspapers in a digital data format to the IP network 27-1,the IP network 27-1 functions as an IP data multicast network fordistributing electronic books and electronic newspapers, with the IPterminals 28-2 to 28-8 representing IP terminals of the users purchasingthe electronic books and electronic newspapers. When the source terminal28-1 is replaced with a TV broadcast audio-visual transmission equipmentand a TV program (i.e., voice and video) is broadcast, this IP networkworks as an IP-based TV broadcast network, with IP terminals 28-2 to28-8 representing TV viewers' IP terminals with TV reception function.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the abovecircumstances and the object of the invention is to provide anintegrated IP network which contains separately a plurality of IPnetworks having various characteristics of, for example, IP telephonenetwork, IP video network, IP electronic text network, best effortnetwork, IP data multicast network, IP-based TV broadcast network or thelike.

The present invention relates to an integrated IP network and the aboveobject of the invention can be achieved by an integrated IP networkincluding: a plurality of IP networks and a plurality of network nodedevices; wherein the network node devices are each connected to one ormore of the IP networks via communication circuits and have theirnetwork node-points connected to external terminals via communicationcircuits; wherein, when the network node device receives an IP packetfrom the external terminal, the following sequence of operations isperformed: in a first case where a network node-point address of thenetwork node-point through which the received IP packet has passed isregistered in an address management table as not specifying a virtualdedicated line connection, a source terminal address, a destinationterminal address and a port number registered in the address managementtable are compared with a source terminal address, a destinationterminal address, a source port number and a destination port numbercontained in the IP packet to find a record containing a networkidentifier indicating a destination IP network to which the IP packet isto be sent; in a second case where a network node-point address of thenetwork node-point through which the received IP packet has passed isregistered in the address management table as specifying a virtualleased line connection, a record containing a network identifierindicating a destination IP network to which the IP packet is to be sentis detected; after the procedure of the first case or the second case iscompleted, the source network node-point address and the destinationnetwork node-point address contained in the detected record are used togenerate an integrated IP network packet which is then sent to thedestination IP network; the integrated IP network packet passes throughan IP packet exchange point and the destination IP network and reachesanother network node device where an integrated IP network header isremoved from the integrated IP network packet to restore the source IPpacket which is then sent to a destination IP terminal; wherein theaddress management table is referenced to select a destination IPnetwork to which the IP packet is to be transferred and the IP packet issent to the destination IP network, and the integrated IP network packetis passed through two or more IP networks of different communicationcompanies within the destination IP network and through IP packetexchange points.

Further the above object of the present invention can be achieved by anintegrated IP network including: a plurality of IP networks and aplurality of network node devices; wherein the network node devices areeach connected to one or more of the IP networks via communicationcircuits and have their network node-points connected to externalterminals via communication circuits; wherein the IP networks eachinclude a dedicated domain name server; the domain name servers each hasa correspondence relationship between IP addresses of the externalterminals and host names of the terminals; upon receiving from anexternal source terminal an IP packet whose destination is one of thedomain name servers, the network node device transfers the received IPpacket to the destination domain name server; the destination domainname server retrieves an IP address of a destination terminalcorresponding to the host name of the destination terminal contained inthe received IP packet and returns the IP packet containing thedestination terminal's IP address obtained to the source terminal; thesource terminal generates a new IP packet having the destinationterminal's IP address obtained from the domain name server in the aboveprocedure and sends the generated IP packet to the network node device;the network node device compares a source terminal address, adestination terminal address and a port number registered in the addressmanagement table with a source terminal address, a destination terminaladdress and a port number contained in the IP packet to find a recordspecifying a destination IP network to which the IP packet is to besent, generates an integrated IP network packet by using the sourcenetwork node-point address and the destination network node-pointaddress contained in the detected record, and sends the generatedintegrated IP network packet to the destination IP network; and theintegrated IP network packet passes through the IP network and the IPpacket exchange point and reaches another network node device where anintegrated IP network header is removed from the integrated IP networkpacket to restore the sending IP packet which is then sent to thedestination IP terminal; wherein the address management table isreferenced to select a destination IP network to which the IP packet isto be transferred and the IP packet is sent to the destination IPnetwork, and the integrated IP network packet is passed through two ormore IP networks of different communication companies within thedestination IP network and through IP packet exchange points.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a conceptual diagram showing an IP transfer according to theconventional Internet;

FIG. 2 is a conceptual diagram showing a multicast type IP transfer;

FIG. 3 is a schematic block diagram showing a first embodiment of thepresent invention;

FIG. 4 is a flow chart showing an example operation performed by anetwork node device of the first embodiment of the present invention;

FIG. 5 is an address management table used in the first embodiment ofthe present invention;

FIG. 6 is an explanatory diagram of a packet to be transmitted andreceived in the first embodiment of the present invention;

FIG. 7 is a flow chart showing another example of operation performed bythe network node device of the first embodiment of the presentinvention;

FIG. 8 is another example of the address management table used in thefirst embodiment of the present invention;

FIG. 9 is a schematic block diagram showing a second embodiment of thepresent invention;

FIG. 10 is a flow chart of an example operation performed by a networknode device of the second embodiment of the present invention;

FIG. 11 is an example of address management table used in the secondembodiment of the present invention;

FIG. 12 is an explanatory view of a packet transmitted and received inthe second embodiment of the present invention;

FIG. 13 is a flow chart showing another example of operation performedby the network node device of the second embodiment of the presentinvention;

FIG. 14 is a schematic block diagram showing a third embodiment of thepresent invention;

FIG. 15 is a diagram showing an address management table used in thethird embodiment;

FIG. 16 is an example of a “packet transmitted and received” which isused in the third embodiment;

FIG. 17 is an example of a “packet transmitted and received” which isused in the third embodiment;

FIG. 18 is an example of a “packet transmitted and received” which isused in the third embodiment;

FIG. 19 is an example of a “packet transmitted and received” which isused in the third embodiment;

FIG. 20 is an example of a “packet transmitted and received” which isused in the third embodiment;

FIG. 21 is a flow chart showing an example operation performed by thenetwork node device of the third embodiment;

FIG. 22 is a diagram showing an IP packet used in the third embodiment;

FIG. 23 is a flow chart showing another example of operation performedby the network node device of the third embodiment;

FIG. 24 is a timing chart showing another example of operation performedby the network node device of the third embodiment;

FIG. 25 is a schematic block diagram showing a fourth embodiment of thepresent invention;

FIG. 27 is an explanatory diagram showing how an IP packet used in thefourth embodiment is transmitted and received;

FIG. 26 is a timing chart showing how the IP packet used in the fourthembodiment is transmitted and received;

FIG. 28 is an explanatory diagram showing how the IP packet used in thefourth embodiment is transmitted and received;

FIG. 29 is an explanatory diagram showing how the IP packet used in thefourth embodiment is transmitted and received; and

FIG. 30 is an explanatory diagram showing how-the IP packet used in thefourth embodiment-is transmitted and received.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the present invention, a plurality of IP networks having variouscharacteristics of IP telephone network, IP video network, IP electronictext network, best effort network, IP data multicast network, IP-basedTV broadcast network and others are virtually installed. An addressmanagement table is set in a network node device installed at an inputpoint through which the integrated IP network is accessed from outside.Addresses of terminals and port numbers for identifying applicationprograms (AP) contained in the terminals are registered in advance inthe address management table. The address and port number written in theIP packet entered into the integrated IP network are compared with theaddresses and port numbers registered in the address management table toroute, inside the integrated IP network, the IP packet to an appropriateIP network. The port number may not be used and only the addresscompared.

Now, embodiments of the present invention will be described by referringto the accompanying drawings.

1. First Embodiment in Which IP Network is Selected According to IPAddress and Port Number:

In FIG. 3, an source terminal 8-1 in a LAN 1, for example, sends an. IPpacket PK01 to a destination IP terminal 8-2 in a LAN 2 via anintegrated IP network 1. Connecting points where communication circuits6-X1 and 6-X2 connect to the network node device 5-X are called “networknode-points”. The network node-point (5-X) of the communication circuit6-X1 is given a network node-point address “G100” used in the integratedIP network 1; the network node-point (5-X) of the communication circuit6-X2 is assigned a network node-point address “G110”; and the networknode-point (5-Y) of the communication circuit 6-Y is assigned a networknode-point address “G200”. The IP packet PK01 includes an address “A100”of the source terminal 8-1, an address “A200” of the destinationterminal 8-2, a source port number “4300” (SP) for identifying theapplication program (AP) in the source terminal 8-1, a destination portnumber “300” (DP) for identifying the application program in thedestination terminal 8-2, and data used by the application program.

The application programs include a voice telephonetransmission/reception program, a video transmission/reception program,an electronic voucher transmission/reception program, and WWW (WorldWide Web) data transmission/reception program based on HTTP (Hyper TextTransfer Protocol). The voice telephone transmission/reception programdenotes a telephone transmission/reception program for IP telephoneusing digital technology. In this embodiment, the terminal addressrepresents an IP address, the port number represents a port number setin a TCP (Transmission Control Protocol) type data block or UDP (UserDatagram Protocol) type data block. In the present invention, the recordin the address management table designates lines in the table andincludes a plurality of data items.

In FIG. 3, denoted 2 is an IP video network which includes an IP videonetwork 2-X of a communication company X and an IP video network 2-Y ofa communication company Y connected together at an IP packet exchangepoint 2-1. Denoted 3 is an IP general purpose network which includes anIP general purpose network 3-X of the communication company X and an IPgeneral purpose network 3-Y of the communication company Y connectedtogether at an IP packet exchange point 3-1. Reference numeral 4 is anIP telephone network which includes an IP telephone network 4-X of thecommunication company X and an IP telephone network 4-Y of thecommunication company Y connected together at an IP packet exchangepoint 4-1. The integrated IP network 1 comprises the IP video network 2,the IP general purpose network 3 and the IP telephone network 4.Further, the network node device 5-X is connected with an addressmanagement table rewriting device 11-1, and the network node device 5-Yis connected with an address management table rewriting device 11-2. Theaddress management table rewriting devices 11-1 and 11-2 can writeaddress and port number into the address management tables in thenetwork node devices 5-X and 5-Y.

In this configuration, the operation of the network will be explained byreferring to a flow chart of FIG. 4. FIG. 4 is a flow chart showing anexample operation of the network node device 5-X. First, an IP packetPK01 is entered into the network from the communication circuit 6-X1 viaa network node-point assigned a network node-point address “G100.” Uponreceiving the IP packet PK01 (Step S100), the network node device 5-Xsearches through a “source network node-point address” column in theaddress management table of FIG. 5 contained in the device to see ifthere is any registered record which has the network node-point addressof “G100” and checks if the record's request identification value is “3”(Step S101). In this embodiment, the request identification value is not“3”, which means that this packet does not specify what is called avirtual dedicated line connection (Case 1). The network node device 5-Xthen reads from the IP packet PK01 the address “A100” (SA) of the sourceterminal 8-1, the address “A200” (DA) of the destination terminal 8-2,the source port number “4300” (SP) for identifying the applicationprogram in the source terminal 8-1, and the destination port number“300” (DP) for identifying the application program in the destinationterminal 8-2 (Step S102). The network node device 5-X then searchesthrough the address management table set in the device to search recordswhose addresses match the source terminal address “A100” (SA) and thedestination terminal address “A200” (DA) of the packet (Step S103). Itshould be noted that normally there are two or more records that satisfythis condition.

Next, because among the extracted records there is one record which haseither the source port number “4300” (SP) or the destination port number“300” (DP), it is searched and identified (Step S104). In thisembodiment, this record is found at the first line, from the top, in theaddress management table of FIG. 5, which has “SA=A100, DA=A200, P=300,N-SA=G100, N-DA=G200” and a network identifier of NWa (Video-net).” Fromthis record, the device picks up the source network node-point address“G100” and the destination network node-point address “G200” and theprocessing moves to step S106. The network node-point address may usethe IP address mentioned above. That is, it may use an address appliedto a third layer of OSI (Open Systems Interconnection), or it may use anaddress applied to a second layer of the OSI, for example, an addressused in a FR (Frame Relay) exchange and an ATM (Asynchronous TransferMode) exchange (e.g., telephone number according to E.164specification).

In the above Step S100, if other IP packet PK05 is entered into thenetwork from the communication circuit 6-X2 through a network node-pointassigned a network node-point address “G110”, the network node device5-X receives the IP packet PK05, searches through the address managementtable in the device to see if there is any record which has a networknode-point address of “G110” in the “source network node-point address”column in the table and also checks whether the “request identification”value of the record is “3” or not (Step S101). In this embodiment, thisrecord has a “request identification” value of “3” (at the second line,from the top, in the address management table), which means that thepacket specifies what is called a virtual dedicated line connection(Case 2). Thus, the processing proceeds to Step S105. Then the deviceretrieves the source network node-point address “G110” and thedestination network node-point address “G210” registered in thisparticular record, before moving to Step S106.

Next, the device adds an integrated IP network header shown in FIG. 6 tothe packet to generate an integrated IP network packet PK11 (Step S106).This step uses the source network node-point address “G100” or “G110”(N-SA) and the destination network node-point address “G200” or “G210”(N-DA) obtained in Step S104 or Step S105. Next, the integrated IPnetwork packet PK11 generated by the above procedure is sent out on acommunication circuit 7-1 according to the specified network identifier“NWa” (IP video network) (Step S107). This communication circuit 7-1 isconnected to the IP video network 2-X run by the communication company Xwithin the IP video network 2.

The above Step S105 switches between the IP telephone network and the IPgeneral purpose network according to whether the received IP packet PK01specifies “NWc” (IP telephone network) or “NWb” (IP general purposenetwork) as the network identifier.

Next, the integrated IP network packet PK11 is sent across the IP videonetwork 2-X, passed through an IP packet exchange point 2-1 and sentacross the IP video network 2-Y of the communication company Y to reachthe network node device 5-Y. The network node device 5-Y, as shown inthe flow chart of FIG. 7, first receives the integrated IP networkpacket PK11 (Step S120), removes the IP network header from the receivedintegrated IP network packet to restore the IP packet destined for LAN(Step S121), and sends the restored IP packet through the communicationcircuit 6-Y to the terminal 8-2 (Step S122).

When the terminal 8-2 in LAN 2 sends out another IP packet PK02 in adirection opposite to that in which the IP packet PK11 was transmitted,the address and the port number in the IP packet are reversed in orderfrom those of the former IP packet. That is, the IP packet has thesource terminal address of “A200,” the destination terminal address of“A100”, the source port number of “300” for identifying the applicationprogram in the source terminal, and the destination port number of“4300” for identifying the application program in the destinationterminal. In this case, an address management table shown in FIG. 8 isused and the port selection specification is also reversed.

The IP packet exchange point 2-1 measures the number of IP packetspassing through this point and the length of time taken by the IPpackets to pass through the point. The communication company X managingthe IP video network 2-X and the communication company Y managing the IPvideo network 2-Y can measure and use the number and time of the passingIP packets as data for calculating the communication charges to the IPpacket senders and receivers. It is also possible to implement thisembodiment such that the IP video network 2-Y of the communicationcompany Y and the IP packet exchange point 2-1 do not exist, i.e., theIP video network 2 includes only the IP video network 2-X of thecommunication company X. In this case, the communication company runningthe IP video network 2 is one company “X”. Similarly, the IP telephonenetwork 4 may include only the IP telephone network 4-X of thecommunication company X.

Next, let us explain about a case where the terminals are videotransmission/reception device or IP telephones, and the communicationcircuit connected to the logic terminals of network node devices isconnected solely to the IP video network 2-X or IP telephone network4-Y. In FIG. 3, a reference numeral 9-1 is a videotransmission/reception device which is connected to the network nodedevice 9-3 via a communication circuit 9-2 and further to the IP videonetwork 2-X via a communication circuit 9-4. A reference numeral 10-1 isan IP telephone which is connected to a network node device 10-3 via acommunication circuit 10-2 and further to an IP telephone network 4-Yvia a communication circuit 10-4. The communication company X is runningthe network node device 9-3 and the communication company Y the networknode device 10-3. The address management table prepared according to thesame principle as that of FIG. 5 or 8 is set in the network node devices9-3 and 10-3.

In this configuration, an IP packet including video informationtransmitted from the video transmission/reception device 9-1 as digitalinformation, for example, can exchange the video digital informationwith the video transmission/reception program in the terminal 8-2 viathe network node device 9-3, the IP video network 2-X, the IP packetexchange point 2-1, the IP video network 2-Y, the network node device5-Y and the communication circuit 6-Y. Likewise, an IP packet includingvoice information transmitted from the IP telephone 10-1 as digital datacan exchange the voice digital information with the telephonetransmission/reception program in the terminal 8-1 via the network nodedevice 10-3, the IP telephone network 4-Y, the IP packet exchange point4-1, the IP telephone network 4-X, the network node device 5-X and thecommunication circuit 6-X1.

In the first embodiment described above, the IP network has beendescribed to include the IP telephone network and the IP video network.The dedicated IP networks may also be provided separately for differentpurposes, for example, IP facsimile network dedicated to facsimile, IPelectronic voucher network dedicated to dealing with electronic voucher,and IP foreign exchange network dedicated to dealing with foreignexchange.

2. Second Embodiment in Which IP Network is Selected According to OnlyIP Address:

As shown in FIG. 9 similar to FIG. 3, a network node-point of acommunication circuit 6-X1 is given a network node-point address “G105”used in the integrated IP network; and a network node-point of acommunication circuit 6-X2 is assigned a network node-point address“G115”. An source terminal 8-3 in LAN 3, for example, sends an IP packetPK03 to a destination terminal 8-4 in LAN 4. The IP packet PK03 includesan address “A105” of the source terminal 8-3, an address “A205” of thedestination terminal 8-4, and transmission data. The transmission datais data handled by a voice telephone transmission/reception program, avideo transmission/reception program, an electronic vouchertransmission/reception program, and a WWW data transmission/receptionprogram based on the known HTTP protocol. The voice telephonetransmission/reception program denotes a telephonetransmission/reception program for IP telephone using digitaltechnology.

In this configuration, the operation of the network will be explained byreferring to a flow chart of FIG. 10. First, an IP packet PK03 isentered into the network from the communication circuit 6-X1 via anetwork node-point assigned a network node-point address “G105”. Thenetwork node device 5-X receives the IP packet PK03 (Step S200),searches through the address management table in the device to see ifthere is any registered record which has the network node-point addressof “G105” in “the source network node-point address” column, and checksif the record's request identification value is “3” (Step S201). In thisembodiment, the request identification value is not “3”, which meansthat this packet does not specify the virtual dedicated line connection(Case 1). The network node device 5-X then reads from the IP packet PK03the address “A105” (SA) of the source terminal 8-3 and the address“A205” (DA) of the destination terminal 8-4 (Step S202) and searchesthrough the address management table set in the device and shown in FIG.11 to find a record whose addresses match the source terminal address“A105” (SA) and the destination terminal address “A205” (DA) of thepacket (Step S203). In this embodiment, this record is found at thefirst line, from the top, in the address management table of FIG. 11,which has “SA=A105, DA=A205, N-SA=G105, N-DA=G205” and a networkidentifier of NWa (Video-net). From this record, the device picks up thesource network node-point address “G105” and the destination networknode-point address “G205” and the processing moves to Step S206. Thenetwork node-point address may use the IP address mentioned above. Thatis, it may use an address applied to a third layer of the OSI, or it mayuse an address applied to a second layer of the OSI, for example, anaddress used in an FR exchange and an ATM exchange (e.g., telephonenumber according to E.164 specification).

In the above Step S200, if other IP packet PK15 is entered into thenetwork from the communication circuit 6-X2 through a network node-pointassigned a network node-point address “G115 ”, the network node device5-X receives the IP packet PK15, searches through the address managementtable in the device to see if there is any record which has a networknode-point address of “G115” in the “source network node-point address”column in the table and also checks whether the request identificationvalue of the record is “3” or not (Step S201). In this embodiment, thisrecord has a request identification value of “3” (at the second line,from the top, in the address management table), which means that thepacket specifies the virtual dedicated line connection (Case 2). Thus,the processing proceeds to Step S205. Then the device retrieves thesource network node-point address “G115” and the destination networknode-point address “G215” registered in this particular record, beforemoving to Step S206.

Next, the device adds an integrated IP network header shown in FIG. 12to the packet to generate an integrated IP network packet PK13 (StepS206). This step uses the source network node-point address “G105” or“G115” (N-SA) and the destination network node-point address “G205” or“G215” (N-DA) obtained by Step S203 or Step S205. Next, the integratedIP network packet PK13 generated by the above procedure is sent out on acommunication circuit 7-1 according to the specified network identifier“NWa” (IP video network) (Step S207). This communication circuit 7-1 isconnected to the IP video network 2-X run by the communication company Xwithin the IP video network 2. The above Step S205 switches between theIP video network and the IP general purpose network according to whetherthe received IP packet PK03 specifies “NWc” (IP telephone network) or“NWb” (IP general purpose network) as the network identifier.

Next, the integrated IP network packet PK13 is sent across the IP videonetwork 2-X, passed through the IP packet exchange point 2-1 and sentacross the IP video network 2-Y of the communication company Y to reachthe network node device 5-Y. The network node device 5-Y, as shown inthe flow chart of FIG. 13, receives the integrated IP network packetPK13 (Step S220), removes the IP header from the received integrated IPnetwork packet to restore the IP packet destined for LAN (Step S221),and sends -the restored IP packet through the communication circuit 6-Yto the terminal 8-4 (Step S222). The IP packet exchange point 2-1measures the number of IP packets passing through this point and thelength of time taken by the IP packets to pass through the point. Thecommunication company X managing the IP video network 2-X and thecommunication company Y managing the IP video network 2-Y can measureand use the number and time of the passing IP packets as data on whichto base the calculation of the communication charges to the IP packetsenders and receivers.

It is also possible to implement the second embodiment such that the IPvideo network 2-Y of the communication company Y and the IP packetexchange point 2-1 do not exist, i.e., the IP video network 2 includesonly the IP video network 2-X of the communication company X. In thiscase, the communication company running the IP video network 2 is onecompany “X”. Similarly, the IP telephone network 4 may include only theIP telephone network 4-X of the communication company X.

3. Third Embodiment Using Individual Domain Name Server:

As shown in FIG. 14, an integrated IP network 31 has an IP audio-visualnetwork 32, an IP data network 33, an IP telephone network 34 and a besteffort network 35. The IP audio-visual network 32 is an IP networksimilar to the IP video network but can transfer both video and itsassociated voice, such as movie and TV broadcast video and its voice.The IP data network 33 has a function similar to that of the IPelectronic text network and can send such data as compressed staticimage data in addition to the electronic text data made up ofcharacters. The best effort network 35 has a function of performing IPtelephone communication, IP audio-visual communication and IP datacommunication and is an IP network that is used by a user who knows thatin the event of a communication traffic congestion during IP transfer,communication delays will occur or the number of IP packets discardedwill increase. A typical example of the IP best effort network is theInternet.

In the integrated IP network 31, network node devices 35-1, 35-2, 35-3,35-4, 35-5 and 35-6 are connected to one of IP networks 31 (IPaudio-visual network 32, IP data network 33, IP telephone network 34 andbest effort network 35) through communication circuits 37-1 to 37-20.The network node-points of the network node devices are connected toexternal terminals 42-1, 43-1, 44-1, 42-2, 43-2, 44-2 of the integratedIP network 31 and internal terminals of LAN 31, LAN 32, LAN 33 and LAN34 via one of communication circuits 36-1, 36-2, 36-3, 36-4, 36-5, 36-6,36-7, 36-8, 36-9, 36-10. The network node devices each have an addressmanagement table which is written with IP addresses of registeredterminals and port numbers for identifying the applications of theterminals.

The IP networks 31 (IP audio-visual network 32, IP data network 33, IPtelephone network 34 and best effort network 35) include dedicateddomain name servers 45-1, 45-2, 45-3, 45-4, 45-5, 45-6, 45-7, 45-8 usedin these networks. These domain name servers have one-to-onecorrespondence between host names assigned to the external terminals42-1 to 44-2 and their IP addresses.

The network node-point of the communication circuit 36-1 is given anetwork node-point address “G361” used within the integrated IP network31. The network node-points represent logical boundaries between thenetwork node devices 35-1 to 35-6 and the external communicationcircuits of the integrated IP network 31. The network node-points areeach assigned a network node-point address. Further, the networknode-point of the communication circuit 36-2 is assigned a networknode-point address “G362”, the network node-point of the communicationcircuit 36-6 is assigned a network node-point address “G366”, thenetwork node-point of the communication circuit 36-7 is assigned anetwork node-point address “G367”, the network node-point of thecommunication circuit 36-8 is assigned a network node-point address“G368”, and the network node-point of the communication circuit 36-10 isassigned a network node-point address “G3610”.

FIG. 15 shows an example of the address management table in the networknode device 35-1. The domain name server is assigned a networknode-point address and an IP address, which are used as an address forsending and receiving IP packets.

Next, the method of communicating from an IP telephone 38-1 in LAN 31 toan IP telephone 40-1 in LAN 33, for example, will be explained byreferring to FIGS. 15 to 23. The IP telephone 38-1 has an IP address of“A381” and the IP telephone 40-1 has a telephone number of “T401”corresponding to the host name of a terminal and an IP address of“A401”. The domain name server 45-3 dedicated for the IP telephonenetwork 34 has an IP address of “A453” and a network node-point addressof “G453”.

The IP telephone 38-1 first sends to a network node device 35-1 an IPpacket PK36 containing the telephone number “T401” of the destinationterminal or destination IP telephone 40-1 (Step S401). The network nodedevice 35-1 reads from the received IP packet PK30 the address “A381”(SA) of the source IP telephone 38-1, the IP address “A453” (DA) of thedestination domain name server 45-3 and a port number “25” and thensearches through the address management table (FIG. 15) set in thenetwork node device 35-1 to find a record whose addresses and portnumber match the address “A381” (SA) of the source IP telephone 38-1,the address “A453” (DA) of the destination domain name server 45-3 andthe port number “25” (Step S402). In this example, this record is foundat the first line, from the top, in the address management table of FIG.15, which has “SA=A381, DA=A453, N-SA=G361, N-DA=G453”. From thisrecord, the device picks up the source network node-point address “G361”and the destination network node-point address “G453”, adds anintegrated IP network header to the packet to generate an IP packetPK31, and transfers the PK31 to the domain name server 45-3 (Step S403).

The domain name server 45-3 receives the IP packet PK31, searchesthrough the internal database and sends back an IP address “A401” thathas a one-to-one correspondence with the telephone number “T401” of thedestination IP telephone 40-1. The network node device 35-1 returns theIP packet 32 to the IP telephone 38-1 (Step S405). With the aboveprocedure, the IP telephone 38-1 obtains the IP address “A401” that hasa one-to-one correspondence with the destination telephone number“T401”.

Next, the IP telephone 38-1 generates a “terminal-to-terminal IP packetPK33” which includes the IP address “A381” of the source IP telephone38-1, the IP address “A401” of the destination telephone, and voice thatis digitized and stored in a payload section (data field) of the IPpacket. The IP telephone 38-1 sends this packet on the communicationcircuit 36-1 (Step S406). Upon receiving the IP packet PK33, the networknode device 35-1 reads from the packet the address “A381” (SA) of thesource IP telephone 38-1, the address “A401” (DA) of the destination IPtelephone 40-1, and a port number “4000” and then searches through theaddress management table (FIG. 15) set in the device to find a recordwhose addresses and port number match the address “A381” (SA) of thesource IP telephone 38-1, the destination terminal address “A401” (DA)of the destination IP telephone 40-1 and the port number “4000” (StepS407). In this example, this record is found at the second line, fromthe top, in the address management table of FIG. 15, which has “SA=A381,DA=A401, port number=4000, NSA=G361, N-DA=G366”. From this record, thedevice picks up the source network node-point address “G361” and thedestination network node-point address “G366”, adds an integrated IPnetwork header to the packet to generate an integrated IP network packetPK34, and transfers the PK34 to the IP telephone network 34-X (StepS408).

The packet PK34 passes through a packet exchange point 34-1 and an IPtelephone network 34-Y. The network node device 35-4 receives the IPpacket PK34 (Step S421), removes the header from the received packetPK34 to restore the IP packet PK33 (Step S422), and sends the IP packetPK33 to the telephone 40-1 (Step S423). In Step S407 the two kinds of IPaddresses and the port number were used for comparison. Some records inthe address management table, however, are not written with their portnumbers. In that case, the port number comparison may be omitted andonly two kinds of IP addresses may be checked.

The network node-point address may be implemented as an IP addressapplied to a third layer of the OSI, as described above. Further, it maybe implemented as an address applied to a second layer of the OSI, forexample, an address used in the field of FR exchange and ATM exchange(such as telephone numbers according to E.164 specification), or it maybe implemented by using a two-layer protocol based on WDM technology.When an address applied to the second layer is used, the “integrated IPnetwork header” shown in FIG. 22 uses a header based on two-layercommunication protocol, such as ATM and WDM.

Next, further explanation will be given by referring to a timing chartof FIG. 24. In FIG. 24, reference numerals 49-1 and 49-2 representterminals of various kinds installed outside the integrated IP network31. The IP packet is sent from the terminal 49-1 to the network nodedevice 35-1 (Step S401), from which it is transferred to the domain nameserver 45-3 dedicated for the IP telephone network 34 (Step S403). Then,the packet is returned from the domain name server (Steps S404 andS405). The terminal 49-1 sends the IP packet to the network node device35-1 (Step S406), and the network node device 35-1 sends it to theintegrated IP packet network (Step S408). The packet passes through thepacket exchange point 34-1 of the IP telephone network 34 and isreceived by the other network node device 35-4 (Step S421), which inturn transfers the IP packet to the terminal 49-2 (Step S423). Theterminal 49-2 can send back the IP packet to the terminal 49-1 (StepS425).

The step of sending and receiving the IP packet, i.e., from Step S431 toStep S455 shown in FIG. 24, can be achieved by using the IP data network33. That is, the data can be transferred between the terminal 49-1 andthe terminal 492 via the domain name server 45-2 dedicated for the IPdata network 33 and the packet exchange point 33-1 in the IP datanetwork 33. Further, the step of transferring the IP packet, i.e., StepsS461 to step 485 shown in FIG. 24, can be achieved by using the IPaudio-visual network 32. That is, the data can be transmitted andreceived between the terminal 49-1 and the terminal 49-2 via the domainname server 45-1 dedicated for the IP audio-visual network 32 and thepacket exchange point 32-1 in the IP audio-visual network 32.

In the above explanation, it is possible to implement this embodimentsuch that the IP audio-visual network 32-Y of the communication companyY and the IP packet exchange point 32-1 do not exit, i.e., the IPaudio-visual network 32 includes only the IP audio-visual network 32-Xof the communication company X. In that case, the communication companyrunning the IP audio-visual network 32 is one company “X”. Similarly,the IP data network 33 may include only the IP data network 33-X of thecommunication company X, and the IP telephone network 34 may includeonly the IP telephone network 34-X of the communication company X.Further, the best effort network 35 may include only the IP telephonenetwork 35-X of the communication company X.

In FIG. 14, reference numerals 46-1, 46-2, 46-3 and 46-4 represent ATMexchange networks, 47-1 and 47-2 FR communication networks, and 48-1 and48-2 optical communication networks. They are used in the IP network ashigh-speed trunk line networks to transfer IP packets. These networksemploy, for example, technologies generally called “FR network-appliedIP transfer” (IP over FR), “ATM network-applied IP transfer” (IP overATM), and “Optical communication network-applied IP transfer” (IP overWDM).

4. Fourth Embodiment Selecting Domain Name Server:

As shown in FIG. 25, an integrated IP network 131 includes an IPaudio-visual network 132, an IP data network 133, an IP telephonenetwork 134, and a best effort network 135. Reference numbers 136-1,136-2, 136-3, 136-4, 136-5, 136-6, 136-7 and 136-8 represent networknode devices. The network node devices 136-1 to 136-8 are connected toone or more of the IP networks via communication circuits. The networknode-points of the network node devices are connected to externalterminals 151, 152, 153, 154 of the integrated IP network 131 and tointernal terminals of LAN 160 and LAN 170 via communication circuits140, 141, 142, 143, 144, 145. The network node devices have an addressmanagement table containing the IP addresses assigned to the externalterminals and the port numbers.

The integrated IP network 131 includes domain name servers 112-1, 112-2dedicated for the IP audio-visual network 132, domain name servers113-1, 113-2 dedicated for the IP data network 133, domain name servers114-1, 114-2 dedicated for the IP telephone network 134, and domain nameservers 115-1, 115-2 dedicated for best effort network 135. These domainname servers have a one-to-one correspondence between the IP address ofthe external terminal and the host name of the terminal. A block 101-1connected to the network node device 136-6 is a DNS selection serverthat has a function of selecting one of the domain name servers 112-1,113-1, 114-1, 115-1. 101-2 connected to the network node device 136-2 isa “DNS selection server” which has a function of selecting one of thedomain name servers 112-2, 113-2, 114-2, 115-2. 137-1 in the integratedIP network 131 represents the range of IP network managed by thecommunication company X, and 137-2 in the integrated IP network 131represents the range of IP network managed by the communication companyY. The IP network 137-1 includes the DNS selection server 101-1 and thedomain name servers 112-1, 113-1, 114-1, 115-1, and the IP network 137-2includes the DNS selection server 101-2 and domain name servers 112-2,113-2, 114-2, 115-2.

Next, the operation of these devices will be explained by referring toFIGS. 26 to 30.

Reference numerals 160-T and 170-T in FIG. 26 represent terminals insideLAN 160 and LAN 170. First, the audio-visual terminal 161 sends an IPpacket 181 to the network node device 136-6 (Step S601); the networknode device 136-6 transfers the IP packet 181 to the DNS selectionserver 101-1 (Step S602); the DNS selection server 101-1 finds an IPnetwork-specifying code contained in “aa.bb.cc.audio-visual.jp” of thedata section of the IP packet, in this case “audio-visual”, and hencetransfers the IP packet 181 of FIG. 27 to the domain name server 112-1for the IP audio-visual network (Step S603). The domain name server112-1 returns to the terminal 161 the IP packet containing an IP addresshaving a one-to-one correspondence with the host name“aa.bb.cc.audio-visual.jp” (Step S605). Then, the terminal 161 sends theIP packet toward the terminal 171 that is located at the IP addressobtained in the above step which matches “aa.bb.cc.audio-visual.jp”(Steps S606 and S607). The terminal 171, upon receiving the IP packet,generates an IP packet for response and returns it to the terminal 161(Step S608).

When the terminal 162 for IP data communication sends an IP packet 182to the network node device 136-6 (Step S611), an operation performed issimilar to the above. What differs from the above operation is that theDNS selection server 101-1 finds the IP network-specifying codecontained in “aa.bb.cc.data.jp” of the data section of the IP packet 182of FIG. 28, in this case “data”, and therefore transfers the IP packetto the domain name server 113-1 for the IP data network (Step S613). Thedomain name server 113-1 returns to the terminal 162 an IP addresshaving a one-to-one correspondence with the host name “aa.bb.cc.data.jp”(Step S615). Next, the terminal 162 sends the IP packet toward theterminal 172 that is located at the IP address corresponding one-to-oneto “aa.bb.cc.data.jp” obtained in the above step (Steps S616 and S617).The terminal 172, upon receiving the IP packet, generates an IP packetfor response and returns it to the terminal 162 (Step S618).

When the IP telephone 163 sends an IP packet 183 of FIG. 29 to thenetwork node device 136-6 (Step S621), an operation performed is similarto the above. What differs from the above operation is that the DNSselection server 101-1 finds the IP network-specifying code contained in“aa.bb.cc.telephone.jp” of the data section of the IP packet 183, inthis case “telephone”, and therefore transfers the IP packet 183 to thedomain name server 114-1 for the IP telephone network (Step S623). Thedomain name server 114-1 returns to the IP telephone 163 an IP addresscorresponding one-to-one to the host name “aa.bb.cc.telephone.jp” (StepS625). Next, the telephone 163 sends the IP packet toward the IPtelephone 173 that is located at the IP address corresponding one-to-oneto “aa.bb.cc.telephone.jp” obtained in the above step (Steps S626,S627). The IP telephone 173, upon receiving the IP packet, generates anIP packet for response and returns it to the IP telephone 163 (StepS628).

When the data section of the IP packet 184 of FIG. 30 from the terminal164 does not contain any code specifying IP audio-visual network, IPdata network or IP telephone network, the DNS selection server 101-1selects the domain name server 115-1 for the best effort network 135.Then, the terminal 164 uses the best effort network 135 to establishIP-communication with the terminal 174. In this way, the IPcommunications between the two terminals can use the IP audio-visualnetwork, the IP data network, the IP telephone network or the besteffort network.

As described above, with the present invention it is possible toeliminate the need to use expensive leased lines and to construct arelatively inexpensive large-scale communication system, without usingthe Internet that does not provide high-speed communication circuits fortransferring TV and other video data and for which there is no personresponsible for planning the expansion of its communication circuitfacilities. Further, because the integrated IP network includes thereina plurality of separated IP networks with a variety of characteristics,such as IP telephone network, IP video network, IP electronic textnetwork, best effort network, IP data multicast network and IP-based TVbroadcast network, the overall cost can-be kept low.

1. An integrated IP network, wherein: said integrated IP networkincludes a plurality of IP networks and a plurality of network nodedevices, said network node devices including address management tablescomprising a plurality of records, a first network node device beingconnected to a first IP network via a first internal line and beingconnected to a second IP network via a second internal line, and asecond network node device being connected to said first IP network viaa third internal line and being connected to said second IP network viaa fourth internal line, first and second records being set at an addressmanagement table in said first network node device, the first recordcomprising a network identifier that designates the first IP network andthe second record comprising a network identifier that designates thesecond IP network a first terminal being connected to said first networknode device by a first network node terminal via a first communicationline, and a second terminal being connected to said second network nodedevice by a second network node terminal via a second communicationline; wherein: when an external IP packet sent from said first terminalis input to said first network node device from said first network nodeterminal, said first network node device compares an IP address and aport number included in said external IP packet with an IP address and aport number included in said first record, and: if the IP address andport number included in said external IP packet and the IP address andport number included in said first record coincide respectively, saidfirst network node device IP-capsulates said external IP packet and thenforms an internal IP packet, said first network node device sending saidinternal IP packet to said first internal line, and said internal IPpacket being transferred in said first IP network and said thirdinternal line and then reaching said second network node device, incompliance with the network identifier in said first record, if said IPaddresses and said port numbers do not coincide, said first network nodedevice compares the IP address and the port number included in saidexternal IP packet with an IP address and a port number included in saidsecond record, and if the IP address and port number included in saidexternal IP packet and the IP address and port number included in saidsecond record coincide respectively, said first network node deviceIP-capsulates said external IP packet and then forms an internal IPpacket, said first network node device sending said internal IP packetto said second internal line, and said internal IP packet beingtransferred in said second IP network and said fourth internal line andthen reaching said second network node device, in compliance with thenetwork identifier in said second record, or if said IP addresses andsaid port numbers do not coincide, said external IP packet is discarded;said external IP packet being restored from said internal IP packet atsaid second network node device, and said external IP packet being sentto said second terminal via said second communication line.
 2. Theintegrated IP network according to claim 1, wherein said comparison onsaid addresses and said port numbers is carried out on addresses only.3. The integrated IP network according to claim 1, wherein said first IPnetwork is an IP telephone network or said second IP network is an IPdata network.
 4. The integrated IP network according to claim 1, whereinsaid first IP network is an IP multicast network or said second IPnetwork is a best-effort network.
 5. The integrated IP network of claim1, further comprising at least one domain name server in one of said IPnetworks; wherein the domain name server establishes a one-to-onecorrespondence between host names assigned to external terminals of thenetwork and the IP addresses of said external terminals; wherein thefirst address management table comprises a third record comprising anaddress of the domain name server; and wherein when said first terminalsends an initial external IP packet including a host name of adestination terminal and having a destination address of a domain nameserver to the first network node device, the first network node devicecompares the IP address of the first terminal and the destinationaddress of the domain name server in said external IP packet with an IPaddress and the address of the domain name server in the third record;and if the IP address of the first terminal and the destination addressof the domain name server in said external IP packet coincide with theIP address and the address of the domain name server in the thirdrecord; the first network node device converts said initial external IPpacket into an internal IP packet directed at the domain name server inthe third record and then sends the internal IP packet to said domainname server, said domain name server forming an internal IP packetincluding the destination terminal IP address having a one-to-onecorrespondence with said host name in said internal IP packet and thensends back said internal IP packet to the first network node device; thefirst network node device returning an external IP packet comprising thedestination terminal IP address to the first terminal, thus allowing thefirst terminal to send to the first network node device an external IPpacket including an IP address, wherein said IP address is thedestination terminal IP address.
 6. An integrated IP network, wherein:said integrated IP network includes a plurality of IP networks and aplurality of network node devices, said network node devices includingaddress management tables comprising a plurality of records, a firstnetwork node device being connected to a first IP network via a firstinternal line and being connected to a second IP network via a secondinternal line, and a second network node device being connected to saidfirst IP network via a third internal line and being connected to saidsecond IP network via a fourth internal line, first and second recordsbeing set at an address management table in said first network nodedevice, the first record comprising a network identifier that designatesthe first IP network and the second record comprising a networkidentifier that designates the second IP network a first terminal beingconnected to said first network node device by a first network nodeterminal via a first communication line, and a second terminal beingconnected to said second network node device by a second network nodeterminal via a second communication line; wherein: when an external IPpacket sent from said first terminal is input to said first network nodedevice from said first network node terminal, said first network nodedevice compares a port number included in said external IP packet with aport number included in said first record, and: if the port numberincluded in said external IP packet and the port number included in saidfirst record coincide respectively, said first network node deviceIP-capsulates said external IP packet and then forms an internal IPpacket, said first network node device sending said internal IP packetto said first internal line, and said internal IP packet beingtransferred in said first IP network and said third internal line andthen reaching said second network node device, in compliance with thenetwork identifier in said first record, if said said port numbers donot coincide, said first network node device compares the port numberincluded in said external IP packet with a port number included in saidsecond record, and if the port number included in said external IPpacket and the port number included in said second record coinciderespectively, said first network node device IP-capsulates said externalIP packet and then forms an internal IP packet, said first network nodedevice sending said internal IP packet to said second internal line, andsaid internal IP packet being transferred in said second IP network andsaid fourth internal line and then reaching said second network nodedevice, in compliance with the network identifier in said second record,or if said port numbers do not coincide, said external IP packet isdiscarded; said external IP packet being restored from said internal IPpacket at said second network node device, and said external IP packetbeing sent to said second terminal via said second communication line.7. The integrated IP network according to claim 6, wherein said first IPnetwork is an IP telephone network, or said second IP network is an IPdata network, an IP multicast network or a best-effort network.